The suspected gunman in the Sikh temple shooting died of a self-inflicted gunshot wound, FBI officials said on Wednesday.

FBI Special Agent in Charge Teresa Carlson said at a news conference that investigators determined Wade Michael Page shot himself in the head after he was shot by police. Authorities previously said an officer had fired the fatal shot.

Page shot a responding police officer in the parking lot at least eight times before another officer wounded Page in a shootout.

The motive behind the shooting remains unknown, and FBI officials say they have not identified anyone other than Page as being responsible. However, the 40-year-old's girlfriend was taken into custody after a handgun was found in her apartment. She is prohibited from possessing a gun as a convicted felon.

Page posted frequent messages on Internet forums for skinheads, urging members to be more active for their cause. He also played in white supremacist heavy metal bands with names such as Definite Hate and End Apathy, and described himself as a member of the "Hammerskins Nation," a skinhead group rooted in Texas that has branches in Australia and Canada, according to the SITE Monitoring Service, a Maryland-based private intelligence firm that searches the Internet for extremist activity.

Suburban Milwaukee police had no contact with Page before Sunday, and his record gave no indication he was capable of such intense violence. Authorities are continuing to sift through Page's life trying to assemble the biography of a man who apparently had few relatives, a spotty work history and a thin criminal record. They have warned they might never learn for certain what drove him to attack total strangers in a holy place.